layout/base/nsRefreshObservers.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsRefreshObservers.h"
   8 #include "nsPresContext.h"
   9
  10 namespace mozilla {
  11
  12 ManagedPostRefreshObserver::ManagedPostRefreshObserver(nsPresContext* aPc,
  13                                                        Action&& aAction)
  14     : mPresContext(aPc), mAction(std::move(aAction)) {}
  15
  16 ManagedPostRefreshObserver::ManagedPostRefreshObserver(nsPresContext* aPc)
  17     : mPresContext(aPc) {}
  18
  19 ManagedPostRefreshObserver::~ManagedPostRefreshObserver() = default;
  20
  21 void ManagedPostRefreshObserver::Cancel() {
  22   // Caller holds a strong reference, so no need to reference stuff from here.
  23   mAction(true);
  24   mAction = nullptr;
  25   mPresContext = nullptr;
  26 }
  27
  28 void ManagedPostRefreshObserver::DidRefresh() {
  29   RefPtr<ManagedPostRefreshObserver> thisObject = this;
  30
  31   Unregister unregister = mAction(false);
  32   if (unregister == Unregister::Yes) {
  33     if (RefPtr<nsPresContext> pc = std::move(mPresContext)) {
  34       // In theory mAction could've ended up in `Cancel` being called. In which
  35       // case we're already unregistered so no need to do anything.
  36       mAction = nullptr;
  37       pc->UnregisterManagedPostRefreshObserver(this);
  38     } else {
  39       MOZ_DIAGNOSTIC_ASSERT(!mAction);
  40     }
  41   }
  42 }
  43
  44 }  // namespace mozilla